Timing
Discoteche open after 10 pm, but punctuality isn’t important. The scene doesn’t really heat up until later, so don't bother arriving much before midnight.
For early evening outings, aperitivo (the Italian version of happy hour, about 6:30–9 pm) at enoteche (wine bars) is the quintessential scene of Roman life where Italians and non-Italians mix for drinks and appetizers.